Milk kefir alters fecal microbiota impacting gut and brain health in mice.

Kefir is a fermented beverage made of a symbiotic microbial community that stands out for health benefits. Although its microbial profile is still little explored, its effects on modulation of gut microbiota and production of short-chain fatty acids (SCFAs) seems to act by improving brain health. This work aimed to analyze the microbiota profile of milk kefir and its effect on metabolism, oxidative stress, and in the microbiota-gut-brain axis in a murine model. The experimental design was carried out using C57BL-6 mice (n = 20) subdivided into groups that received 0.1 mL water or 0.1 mL (10% w/v) kefir. The kefir proceeded to maturation for 48 h, and then it was orally administered, via gavage, to the animals for 4 weeks. Physicochemical, microbiological, antioxidant analyzes, and microbial profiling of milk kefir beverage were performed as well as growth parameters, food intake, serum markers, oxidative stress, antioxidant enzymes, SCFAs, and metabarcoding were analyzed in the mice. Milk kefir had 76.64 ± 0.42% of free radical scavenging and the microbiota composed primarily by the genus Comamonas. Moreover, kefir increased catalase and superoxide dismutase (colon), and SCFAs in feces (butyrate), and in the brain (butyrate and propionate). Kefir reduced triglycerides, uric acid, and affected the microbiome of animals increasing fecal butyrate-producing bacteria (Lachnospiraceae and Lachnoclostridium). Our results on the brain and fecal SCFAs and the antioxidant effect found were associated with the change in the gut microbiota caused by kefir, which indicates that kefir positively influences the gut-microbiota-brain axis and contributes to the preservation of gut and brain health. KEY POINTS: • Milk kefir modulates fecal microbiota and SCFA production in brain and colon. • Kefir treatment increases the abundance of SCFA-producing bacteria. • Milk kefir increases antioxidant enzymes and influences the metabolism of mice.

The role of IL-10 in regulating inflammation and gut microbiome in mice consuming milk kefir and orally challenged with S. Typhimurium.

Kefir has been suggested as a possible bacterial prophylaxis against Salmonella and IL-10 production seems to be crucial in the pathogenesis of salmonellosis in mice. This study evaluated the role of IL-10 in the inflammation and gut microbiome in mice consuming milk kefir and orally challenged with Salmonella enterica serovar Typhimurium. C57BL wild type (WT) (n = 40) and C57BL IL-10-/- (KO) (n = 40) mice were subdivided into eight experimental groups either treated or not with kefir. In the first 15 days, the water groups received filtered water (0.1 mL) while the kefir groups received milk kefir (10% w/v) orally by gavage. Then, two groups of each strain received a single dose (0.1 mL) of the inoculum of S. Typhimurium (ATCC 14028, dose: 106 CFU mL-1). After four weeks, the animals were euthanized to remove the colon for further analysis. Kefir prevented systemic infections only in IL-10-/- mice, which were able to survive, regulate cytokines, and control colon inflammation. The abundance in Lachnospiraceae and Roseburia, and also the higher SCFA production in the pre-infection, showed that kefir has a role in intestinal health and protection, colonizing and offering competition for nutrients with the pathogen as well as acting in the regulation of salmonella infectivity only in the absence of IL-10. These results demonstrate the role of IL-10 in the prognosis of salmonellosis and how milk kefir can be used in acute infections.

Efeitos da corticoterapia materna nos valores hemogasométricos de cordeiros nascidos a termo e prematuros / Effects of maternal blood gas values corticotherapy of Lambs born at term and premature

O objetivo do estudo foi avaliar as variáveis hemogasométricas de cordeiros nascidos a termo e prematuros do nascimento às 48 horas de vida. Foram constituídos quatros grupos experimentais: PN (cordeiros nascidos de parto normal, n=15, média de 146 dias de gestação); PNDEX (cordeiros nascidos de parto normal, cujas mães receberam 16 mg de dexametasona aos 141 de gestação, n=8, média de 143 dias de gestação); PRE (cordeiros prematuros nascidos de cesarianas aos 138 dias de gestação, n=10) e PREDEX (cordeiros prematuros nascidos de cesarianas aos 138 dias de gestação, cujas mães receberam 16 mg de dexametasona dois dias antes do parto, n=9). Imediatamente após o nascimento, os cordeiros de todos os grupos apresentaram quadro de acidose respiratória (pH baixo e pCO2 elevada), com maior ênfase nos animais prematuros. A concentração de HCO3 - diminuiu entre 15 e 60 minutos de vida, principalmente nos grupos PRE e PREDEX, com posterior aumento no M24h. Os valores de diferença de base foram menores nos cordeiros prematuros, os quais apresentaram respiração abdominal, intensa dispneia e grande quantidade de líquido pulmonar. A estabilização do equilíbrio ácidobase ocorreu em todos os animais ao longo das primeiras 24 horas de vida. A dexametasona teve influência positiva sobre a condição clínica dos animais prematuros, resultando em adequada ventilação e perfusão tecidual, o que garantiu maior taxa de sobrevivência.(AU)

The aim of the study was to evaluate blood gas parameters of full-term and premature lambs from birth to 48 hours of life. Four experimental groups were formed: NDG (normal delivery group - lambs vaginally delivered, n=15, average of 146-day gestation); NDEXG (normal delivery with dexamethasone group - lambs vaginally delivered whose mothers received 16 mg of dexamethasone at 141 days of gestation, n=8, average of 143-day gestation); PRE (premature lambs born by cesarean section at 138 days of gestation, n=10) and PREDEX (premature lambs born by cesarean section at 138 days gestation, whose mothers received 16mg of dexamethasone two days before, n=9). Immediately after birth, lambs from all groups showed respiratory acidosis (low pH and high pCO2), most obviously in premature animals. The concentration of HCO3 - was lower between 15 and 60 minutes of life, especially in PRE and PREDEX groups with subsequent increase in M24h. The values of base excess were lower in premature lambs, which showed abdominal breathing, severe dyspnea and lots of lung fluid. The stabilization of acid-base balance occurred in all animals during the first 24 hours of life. Dexamethasone had a positive effect on the clinical condition of the premature lambs, resulting in adequate ventilation and tissue perfusion, which guaranteed higher survival rate.(AU)

Aplicação materna de glicocorticoide nos parâmetros vitais de cordeiros nascidos a termo e prematuros / Maternal glucocorticoid in vital parameters of full-term and preterm lambs

O objetivo deste trabalho foi avaliar a influência do glicocorticoide sobre parâmetros vitais de cordeiros nascidos a termo e prematuros, do nascimento às 48 horas de vida. Foram constituídos quatros grupos: PN (cordeiros nascidos de parto normal, n=15, média de 146 dias); PNDEX (cordeiros nascidos de parto normal, cujas mães receberam 16mg de dexametasona aos 141 dias de gestação, n=8, média de 143 dias); PRE (cordeiros prematuros nascidos de cesarianas aos 138 dias de gestação, n=10); e PREDEX (cordeiros prematuros nascidos de cesarianas aos 138 dias de gestação, cujas mães receberam 16mg de dexametasona dois dias antes, n=9). As frequências cardíaca e respiratória variaram ao longo do período, com os maiores valores nos grupos de partos normais. A temperatura retal diminuiu em todos os grupos nos primeiros 60 minutos de vida, sendo os menores valores observados nos cordeiros prematuros, e o escore Apgar foi mais alto nos animais nascidos em tempo gestacional normal. Os cordeiros prematuros apresentaram menor vitalidade e menor taxa de sobrevivência, entretanto, menor taxa de mortalidade foi observada nos prematuros sob influência da dexametasona.

The aim of the study was to evaluate the influence of glucocorticoids on vital parameters of full-term and preterm lambs from birth to 48 hours of life. Four experimental groups were formed: NDG (normal delivery group - lambs vaginally delivered, n=15, average of 146-day gestation); NDEXG (normal delivery with dexamethasone group - lambs vaginally delivered whose mothers received 16mg of dexamethasone at 141 days of gestation, n=8, average of 143-day gestation); PRE (premature lambs born by cesarean section at 138 days of gestation, n=10) and PREDEX (premature lambs born by cesarean section at 138 days gestation, whose mothers received 16mg of dexamethasone two days before, n=9). Heart and respiratory rates had variations during the observation period, with the highest mean values in the groups of normal deliveries (NDG and NDEXG). Rectal temperature decreased in all groups in the first 60 minutes of life, with the lowest mean values in premature lambs (PRE and PREDEX) and the Apgar score was higher in animals delivered at normal gestational time. Preterm lambs had lower vitality and chance of survival, however, lower mortality rate was observed in offspring of ewes that received dexamethasone two days before surgery.